Cat

Posted by ESC on November 06, 1999

In Reply to: Let the cat out of the bag posted by Bruce Kahl on November 06, 1999

: : Have also heard that this applies to dropping/weighing anchor on sailing ships.

: I am not 100% on this but at medieval markets, unscrupulous traders would display a pig for sale. However,the pig was always given to the customer in a bag containing something that wiggled, and it was only later that the buyer would find he'd been conned when he opened the bag to reveal that it contained a cat, not a pig.
: Therefore, "letting the cat out of the bag" revealed the secret of the con trick.

You're right about the pig in a poke/cat out of the bag connection. The term might have two meanings. But the only related nautical term I could find was "cat. The catapult used to launch planes on an aircraft carrier." That's from Slang by Paul Dickson.